Blender - Blender is the open source, cross platform suite of tools for 3D creation.
GoodBarber - GoodBarber is a mobile app creation platform.
FreeCAD - An open-source parametric 3D modeler
Dropsource - Mobile development platform for building native iOS & Android apps
meshmixer - meshmixer is an experimental 3D modeling tool for making 3D mashups without too much hassle.
Siberian CMS - Siberian is an Open-Source and Free App Maker. Unlimited Push Notifications. Unlimited features. Fully Customizable. Download it and build your own app now!